Which wide angle, Canon mount, for star field astro-landscapes?

I would like to try my hand on astro-landscapes, and want to hear any experiences with less expensive wide angle lenses. L lenses are out for now. I am curious about sharpness for star fields.

APS-C (60D). My current crop of wide angle zooms (15-85mm, 8-16mm) are slow maximum aperture, f/3.5-4.5. My only fast lens is a 60mm f/2.8 macro.

Possible contenders could be:

Canon 35mm f/2.0  ($310.00)

Samyang 35mm f/1.4 ($450.00)

Various non-L Canons: 20mm f/2.8, 24mm f/2.8 (not the 1.4LII, that's too expensive), 28mm f/1.8, 28mm f/2.8.

Sigma primes: 20mm f/1.8, 24mm f/1.8, 28mm f/1.8, 30mm f/1.4

Legacy lenses, with non-reporting simple adapter?